光子学报, 2016, 45 (1): 0111001, 网络出版: 2016-03-22
飞轮微振动对空间相机调制传递函数的影响
Effect of Flywheel Micro-vibration on Modulation Transfer Functionof Space Camera
微振动 飞轮 空间相机 集成建模 调制传递函数 Micro-vibration Flywheel Space camera Integrated modeling Modulation Transfer Function(MTF)
摘要
结合集成建模法和光线追迹法研究飞轮微振动对相机成像质量的影响.采用集成建模法, 建立飞轮微振动的扰动模型、卫星和相机的有限元模型, 进行瞬态响应分析, 得到6个方向力或力矩单独作用下相机各反射镜随时间变化的位移.采用光线追迹法, 由反射镜位移和入射光线, 根据折射定律计算折射后光线的位置、方向及与光轴的夹角.由得到像面处的光斑坐标和位移, 运用运动统计矩计算系统调制传递函数.结果表明: 响应周期与激励周期无关;激励的作用时间长度和采样时间长度均会影响调制传递函数;不同方向振动激励造成的调制传递函数变化的大小不同, 而不同方向对包含原光学系统的调制传递函数的影响类似仅振动对调制传递函数的影响;当振动分别作用My、Mz值时衰减最大, 达到0.1左右.该方法较理论推导简便快捷, 能获取微振动与调制传递函数的关系, 为系统优化设计和隔振措施提供参考.
Abstract
To investigate the flywheel micro vibration effect on the camera imaging quality, the method of integrated modeling and ray tracing was used. The integrated modeling is to set up disturbance model of the micro vibration of the flywheel, the finite element model of the satellite and the camera. By the transient response analysis, the displacement of all the mirror with the time under the action of force or moment in 6 directions respectively is obtained. The ray tracing is based on reflection mirror displacement and the incident light, according to the refraction law to calculate the location and direction of the ray, and the angle between the ray and the optical axis. Then, the spot coordinates and displacements of the image plane are obtained, and the Modulation Transfer Function (MTF) of the system is calculated by using the statistical moment of motion. The results show that the response period has nothing to do with the excitation period; the length of excitation time and sampling time affect the MTF; different direction vibration causes the change of MTF of different sizes, indicating the size of angular and linear vibrations on MTF; and different direction effect on MTF is similar between with the original optical system and with only vibration, where MTF attenuation reaches maximum when My, Mz is loaded respectively, up to about 0.1. The research method is simple and fast, and the relationship between the micro vibration and the MTF is obtained, which provides reference for the system design and vibration isolation.
邓长城, 安源, 母德强, 解鹏, 于丹. 飞轮微振动对空间相机调制传递函数的影响[J]. 光子学报, 2016, 45(1): 0111001. DENG Chang-cheng, AN Yuan, MU De-qiang, XIE Peng, YU Dan. Effect of Flywheel Micro-vibration on Modulation Transfer Functionof Space Camera[J]. ACTA PHOTONICA SINICA, 2016, 45(1): 0111001.